32 RELATIONSHIPS OF THE COCCACE^ 



creasingly clear that the cocci form a natural group of 

 unusual definiteness. It is difficult to add to Migula's 

 description any other single character which is common 

 to the family. Yet a consideration of the properties of 

 the members of the group makes it clear that they are 

 mutually interrelated and all sharply separated from the 

 rod-shaped bacteria, except perhaps at one end of the 

 series which they form. 



The subdivisions of the Coccaceae, however, have been 

 less satisfactorily established than the status of the family 

 itself. No other group of the bacteria has been bur- 

 dened with more generic names. Ascococcus, Bacteri- 

 dium, Cohnia, Diplococcus, Gonococcus. Hyalococcus, 

 Lampropedia, Leucocystis, Leuconostoc, Merismopedia, 

 Merista, Micrococcus, Microhaloa, Monas t Pediococcus, 

 Planococcus, Planosarcina, Sarcina, Staphylococcus, Strep- 

 tococcus, Tetracoccus, is a partial list. Many of these 

 names date back to the early days of bacteriology and are 

 due to the attempts of botanists, trained in other fields 

 than bacteriology, to create genera on slight morpholo- 

 gical grounds alone. Merismopedia, Hyalococcus, Staphy- 

 lococcus, and Tetracoccus are examples of this sort; and 

 Fischer's Pediococcus is a more modern instance of the same 

 tendency. Migula (1897) made an exhaustive review of 

 the earlier attempts at generic classification of the cocci 

 and eliminated as synonyms, or imperfectly charac- 

 terized, all previous genera but three, Streptococcus, 

 Micrococcus, and Sarcina. He added two new genera, 



